Modulation of PBAT/PU Blends by Gallic Acid-Modified MOF-5: Mechanical, Antimicrobial, and Antioxidant Enhancement Mechanism of a Novel Biodegradable Food Packaging Film

Conventional food packaging plastics are difficult to degrade under natural conditions, causing long-lasting environmental harm. With the aim of addressing this problem, this study develops a novel biodegradable composite food packaging film based on polybutylene adipate-terephthalate (PBAT) and polyurethane (PU). MOF-5 nanoparticles are prepared via the ambient temperature precipitation method and modified with gallic acid (GA). PBAT/PU/GA@MOF-5 composite films are fabricated by the solvent casting method. The findings demonstrate that the introduction of GA@MOF-5 enhances the compatibility between PBAT and PU and reduces phase separation; therefore, it augments the mechanical performance of the resultant composite films. These composite films manifest excellent mechanical, thermal degradation, and antioxidant properties, performing remarkably in apple freshness tests. Furthermore, the incorporation of GA@MOF-5 endows the films with significant antimicrobial activity, showing restraint on the proliferation of both Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). This study offers an innovative idea for biodegradable food packaging materials design and expands the application prospect of the PBAT/PU composite system in the food packaging field.